2011 up is a Dealer or Locksmith. 3 minutes, $40.00.
If I understand what is desired, a previous 09 Gov't Mtrs of mine required the laptop mounted Tech II software for pairing; think that requirement happened before 2011.
It wasn't until after the fact I discovered up to four remotes could be paired and the tech left one of my then MIA remotes in the system, duh...
$40? Wish I had been so lucky... In my neck of the woods, once the obligatory shop materials, hazardous material disposal fees, and taxes were factored in at the auto repair shop, the bill approached north of $50.
I have programmed my 2015 Impala before. There is a little slot in the center console that the key goes into. Then I think there was some magical button combination to start the programming. I do know that when It was programming the LCD screen said it was and there was a % bar showing how long until complete.